1. Field of the Invention
The present invention relates to a touch display panel and a touch sensing unit thereof, and more particularly to a touch display panel with non-transparent bridge lines of a high electrical conductivity electrically connected to transparent conductive pads, and a touch sensing unit thereof. The line width of each of the non-transparent bridge lines is substantially between 0.5 micrometer and 10 micrometers, and an aperture ratio of pixel regions of the touch display panel occupied by the non-transparent bridge lines is substantially between 0.1% and 5%.
2. Description of the Prior Art
In present consumer electronics, tablet personal computers, personal digital assistants (PDA), mobile phones, global positioning systems (GPS), multimedia players and other portable electronic devices widely apply touch panels to replace conventional keyboards as the data communicational interface between human and the electronic devices, such that the size of the electronic devices can be reduced.
Conventional touch panels mainly utilize a touch sensing unit including a plurality of first transparent sensing pads aligned along a first direction (i.e. a horizontal direction) and a plurality of second transparent sensing pads aligned along a second direction (i.e. a vertical direction) to achieve the touch input function. When an input device such as a finger is touched or pressed on a certain position of the touch panel, at least one of the first transparent sensing pads forms a capacitor with the input device and at least one of the second transparent sensing pads forms another capacitor with the input device. A reading circuit of the touch display panel determines the position of the input device through correlating the capacitance between the input device and the first transparent sensing pads and the capacitance between the input device and the second transparent sensing pads. The transparent sensing pads are made of a transparent conductive material, but the transparent conductive material has a higher resistance so that the touch input signals cannot be easily identified when the transparent conductive material is applied in a large size touch panel. Therefore, a metallic bridge line of a lower resistance is often used to electrically connect adjacent transparent sensing pads in order to reduce an overall resistance of the touch sensing unit and increase the touch sensitivity of the touch panel. However, since the metallic bridge line is made of a non-transparent material, the metallic bridge line would cause the aperture ratio of the touch display panel to decrease when the line width of the metallic bridge line is too broad. In addition, during the fabrication of the metallic bridge lines of conventional touch panels, breakages of the metallic bridge lines often occur due to over etching, and thereby the breakages affect the yields of the touch panels. Therefore, the conventional method utilizing the metallic bridge lines to connect the transparent sensing pads still requires further improvements.